The document U.S. Pat. No. 8,253,548 B2 describes an elevator system with an elevator control unit which exchanges data with an elevator control by a non-wired connection. The elevator control unit also exchanges data with a display unit.
The document U.S. Pat. No. 7,426,981 B2 describes an elevator system with Piconet modules, which exchange data by way of a communications network (Bluetooth) with a non-wired connection. A mobile communications terminal apparatus, which is connected with the communications network having a non-wired connection and which comprises a Piconet module, can in that case acquire data of the elevator installation by transmission.
The document US 2007/0041352 A1 describes a method for detecting the location of an elevator control unit from which a call request has been made. The location of the elevator control unit is determined in a mobile communications network on the basis of the signal strength and the elevator car is dispatched to the corresponding floor of the elevator control unit.
The document EP 1415947 A1 discloses a device for remote maintenance and monitoring of an elevator installation with at least one input for detection of first signals from an elevator control and/or from a sensor with at least one output of second signals to a telecommunications network and with at least one processor and data memory, wherein a set of remote maintenance functions is stored in the data memory and wherein one of these remote maintenance functions is activatable. Data from a sensor or the elevator control are permanently transferred by way of the telecommunications network to a service center.
In elevator installations, use is frequently made of a point-to-point connection or a multi-hop method for a non-wired connection or mobile communication. By point-to-point connection there is to be understood in telecommunications a direct connection without intermediate stations. By contrast, in the case of a multi-hop method data are transferred by way of intermediate stations. The transfer from one station to the next is called hop. In general, distinction is made between single (or simple) hop connections in which exactly one station or hop lies between transmitter and receiver and multi-hop connections in which the data (packets) are passed on by way of several intermediate stations. In multi-hop communications networks reference is also made to the n-hop proximity of a station, wherein n is replaced by a natural number. These are all network junctions which can be reached from the intermediate station under consideration by way of at most n hops. The hop number is the number of steps which a packet has to cover on the route from the transmitter to the receiver, wherein the number of intermediate stations lying along this path is smaller by one.
A disadvantage of such a method is that such communication networks need a substantial radio range and antenna power so that a secure communication can be guaranteed. In addition, use is frequently made of complex network protocols which generate a high traffic load due to security requirements in the transmission of data. Thus, a more secure and reliable connection set-up, i.e. a reliable delivery of data packets and guarantee of fault-free transmission between the units participating in the communication, can indeed be ensured, but the (communications) units have a high energy consumption due to network protocols of that kind.